Piezoelectric device holder



PZEZOELEGTRIC DEVICE HOLDER.

Filed NOV. 4, 1941 Z9 Charles F. Baldwin,

by Wan/1 75 His Attohneg.

Patented Aug. 18, 1942 PIEZOELECTRIC DEVICE HOLDER Charles F. Baldwin,Schenectady, N. Y., assignor to General Electric Company, a corporationof New York Application November 4, 1941, Serial No. 417,816 4 Claims.(Cl. 17132'l) My invention relates to piezoelectric devices, and has foran object to provide an improved and simplified holder for a pluralityof such devices.

When a plurality of high frequency piezoelectric devices is arranged ina single holder with a double-faced electrode interposed between eachpair of adjacent piezoelectric devices, difficulties arise in providingsuitable connections from the respective electrodes to terminals on theholder.

Quartz crystal vibrators for operation at high frequencies are thin. Forexample, such vi,- brators for operation in the range from 2 to 8megacycles, may be from fifty to twelve thousandths of an inch thick.Electrodes for such devices may conveniently be made 1 3' inch or lessin thickness, so that a large number of such devices and electrodes maybe stacked in small space. For example, a typical assembly oftwenty-five quartz crystal vibrators and twenty-six electrodes stackedalternately may be less than 3 inches long. Standard pin terminals areusually mounted not less than A inch apart, so that a single row of suchterminals is twice as long as the stack, thereby making connectionsdiificult. If twenty-seven such terminals be spaced in three rows andnine columns, the overall length can readily be made the same as thestack and interconnection is facilitated.

It is an object of my invention to provide such an assembly ofpiezoelectric devices in a holder having a plurality of rows and columnsof terminals with improved and simplified means whereby connections maybe completed between electrodes and corresponding terminals with minimumpossibility of short circuits between electrodes.

It is also an object of my invention to provide such an improvedarrangement which occupies a minimum of space and is easily manufacturedand rugged in use.

The features of my invention which I believe to be novel are set forthwith particularity in the appended claims. My invention itself, both asto its organization and manner of operation, together with furtherobjects and advantages thereof may best be understood by reference tothe following descriptiontaken in connection with the accompanyingdrawing in which Fig. l is an elevational side view partly in section,of one modification of my invention, and Fig. 2 is a sectional view inperspective of one end of the modification of Fig. 1.

In Fig. 1 there is illustrated a holder which includes a lowerrectangular wall II] with integral sides II and right and left ends I2and I3 respectively. A lid I4 is fastened to the sides II and ends I2and I3 of the holder by means of suitable screws I5. The Wall I0, sidesII, ends I2 and I3, and the lid I4 are all formed of insulatingmaterial, preferably a moldable thermosetting resin. The lid I4 may beprovided with shoulders I6 which engage the sides II and ends I2 and I3of the holder to form a good joint therebetween. If desired, a gasketmay be provided between the lid I4 and the holder for sealing the holderagainst the entrance of moisture and foreign matter.

Within the lower portion of the holder I0, including the lower wall I0,sides II, and ends I2 and I3, a plurality of electrodes I1, I8, I9 20,2| are placed alternately between a plurality of quartz crystalvibrators 22, 23, 24 25, 26. The electrodes may be of any suitable formand, as shown, are rectangular, each electrode having each facecentrally recessed a small amount. A spring 21 is placed between theright end I2 of the holder and the adjacentend of the stack ofelectrodes I'I, I8, I9 20, 2I and vibrators 22, 23, 24 25, 26 tomaintain such stack closely pressed together and held against theopposite end I3 of the holder,

A connection, to be described in detail later, is provided from each ofthe electrodes Il, I8, I9 20, 2I to a corresponding pin terminal, suchas connection 28 from electrode Il to terminal 29. The terminal 29 andthe space between it and the adjacent terminal 30 is considerablygreater than the thickness of electrode I1 and the adjacent quartzcrystal vibrator 22, and is much greater than the thickness of vibrator26 and electrode 2|. As shown in Fig. 1 the terminals which are shownare connected to every third electrode. As may be seen more clearly inFig. 2, behind the terminal 29 there is a second similar pin terminal 3Iand a third terminal 32.

Ribs 33 and 34 are formed inside the holder integral with the lower wallI0, and extending longitudinally from one end I2 tothe outer end I3 ofthe holder. Three channels 35, 36 and 31 are formed in the holder bytheribs 33 and 34, and in these channels the inside ends of the terminals29, 3I and 32 and the respective connections from such terminals to thecorresponding electrodes II, I8 "and I9 are accommodated.

The ribs 33 and 34 are of suflicient depth to maintain the stack ofelectrodes and vibrators such terminals underneath such triads.

' thickness.

spaced from the terminals 29, 3| and 32 and the correspondingconnections, so that undesirable short circuits therebetween areprevented. By the use of these ribs 33 and 34 it is possible to arrangethe terminals in rows and columns, as illustrated, and to makeconnections from each of the terminals in a single column to acorresponding one of three adjacent electrodes without having any oneterminal or corresponding connection'short circuit with any otherconnection.

As may be seen clearly in Fig. 2, in which the right end electrode l1and the adjacent vibrator 22 are partially broken away at the lowerright hand corner, the connecting conductor 28 is embedded in the endelectrode I! and extends through the channel 35, underneaththe secondand third electrodes l8 and H! to the terminal 29 into which theconductor 28 is conductively fastened, as by soldering. A similarconnecting conductor 38 is embedded in the second electrode l8 andextends through the channel 36, underneath the third electrode l9 to theterminal 3|, into which this conductor 38 is conductively fastened. Athird similar connecting conductor 39 is embedded in the third electrode19 and, since this electrode I9 is almost vertically above the terminal32, the conductor 39 extends downward through the channel 31 into theterminal 32, into which it is conductively fastened.

Succeeding triads of electrodes are similarly connected throughconductors extending respectively through channels 35, 36 and 31 tocorresponding terminals in succeeding columns of The ribs 33 and 34 holdthe electrodes and vibrators away from the lower Wall 50 of the holder adistance sufiicient to insure that no connecting conductor can make ashort circuit to any other connecting conductor or terminal except thatto which it is connected. .For example, the third electrode I9, as maybe seen clearly in Fig. 1, is

. held up by the rib 33 and thereby prevented from touching theconductor 28 or the terminal 29 connected thereto.

It will be noted upon inspection of Fig. 1 that the piezoelectricvibrators are arranged in the stack of electrodes and vibrators in orderof That is, the thinnest vibrator 26 is at the left end of the stack,and vibrators to the right thereof are progressively thicker, the

thickest vibrator 22 being at the right. end of the stack. Although itis not necessary that the vibrators be arranged in such order, it is atpresent preferredto arrange them in such fashion.

Afterthe vibrators have been arranged as desired, the pin terminals 29,30, 3|, 32, etc., are

. somewhat differently.

fastened into the lower wall If! equally spaced apart in rows andcolumns, and so positioned with respect to the electrodes l1, I8, ['920, 2| asto avoid the possibility of any terminal being touched by theconductor from an adjacent terminal in the same row. In Fig. 1, theterminals are so spaced that the terminal 29 cannot make contact withthe conductor 40 of the terminal 30 in the second column. Similarly, thethird terminal behind terminal 4| in the left-hand column of terminalsin Fig. 1 is spaced sufiiciently from the conductor 42- of the thirdterminal behind terminal 43 in the column next to the leftthat there isno possibility of contact therebetween.

or more, it may be desirable to arrange them One arrangement by whichthe electrodes may be spaced somewhat more uniformly results by stackingthe thickest vibrator 22 first, the thinnest vibrator 26 second, thenext thickest vibrator 23 third, the next thinnest vibrator 25 fourth,and so on to a vibrator 44 of medium thickness at the other end of thestack. The electrodes stacked between such vibrators are more uniformlyspaced and may, in certain cases, provide more convenient connections tothe terminals.

By the use of the ribs 33 and 34 I am enabled to construct a holder forpiezoelectric devices in which a large number of such devices andcorresponding electrodes are contained in a small space and areconveniently connected to terminals arranged in rows and columns so thatthey are spaced apart by satisfactory distances. It is obvious thatvarious numbers of terminals, electrodes, and piezoelectric devices,different from those illustrated, may be used without departing from thespirit of my invention. Similarly, the terminals may be arranged indifferent numbers of rows and columns.

It is obviously within the scope of my invention that the pins 29, 30,3|, 32, 4|, 43 may take any suitable form for completing circuits forthe electrodes ll through 2|. Such suitable forms, other than thatshown, may, for example, be screws, posts, switch contacts, or the like.

While I have shown and described a particular embodiment of myinvention, itwill be ob:

vious to those skilled in the art that changes and modifications may bemade without departing from my invention in its broader aspects, and I,therefore, aim in the appended claims to cover all such changes andmodifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In combination, an insulating terminal strip to which a plurality ofterminals is aflixed, said terminals being spaced apart at least apredetermined distance, a plurality of conducting members spaced alongsaid strip at less than said predetermined distance, said pluralityofterminals corresponding in number to the number of said members, saidterminals being afilxed along said strip in a plurality of rows witheach of said terminals positioned in proximity to a correspondingmember, means lying between each adjacent pair of rows of saidterminalsfor maintaining said members separated from said strip whereby openchannels are defined between each row of said terminals and saidmembers, and

means passing through each respective channel for connecting each orsaid members to its corresponding terminal, said means being spaced fromthe remaining terminals, members, and connecting means associated withsaid channel, whereby the possibility of undesired short circuitsbetween said connecting means, terminals, and members is minimized.

2. In combination, an elongated insulating terminal strip to whichterminals maybe affixed, said terminals being spaced apart at least apredetermined distanee, a plurality of conducting plates disposedtransversely tov saidstrip and spaced apart therealong at less than saidpredetermined distance, a plurality of rows of terminals disposedlengthwiseof said strip, the number of said terminals corresponding tothe number of said plates and each of said terminals being positioned inproximity to a corresponding plate, insulating spacer means lyingbetween each adjacent pair of rows of said terminals for maintainingsaid plates separated from said strip whereby open channels are definedbetween each row of said terminals and said plates, and a conductingmember passing through each respective channel for connecting each ofsaid plates .to its corresponding terminal, said conducting membersbeing spaced from the remaining terminals, plates and conducting membersassociated with said channel, whereby the possibility of undesired shortcircuits between said conducting members, terminals and plates isminimized.

3. In combination, a plurality of piezoelectric yibrators and aplurality of electrodes therefor arranged alternately in a stack, aholder for said stack having a side wall and a rib on said wall againstwhich a side of said stack rests, said stack, said Wall and said ribdefining an open channel between said stack and wall on each side ofsaid rib, a row of terminals afiixed to said wall on each side of saidrib and extending into a respective channeL'and a conductor passingthrough a respective channel from eachof said electrodes to acorresponding terminal in proximity to said electrodes, whereby thepossibility of undesirable short circuits between said electrodes, saidconductors and said terminals is minimized.

4. In combination, a container having a side wall, a plurality ofpiezoelectric devices and a plurality of electrodes therefor stackedalternately along said wall, a terminal for each of said electrodesaffixed in said wall in proximity to a corresponding electrode, saidterminals being spaced apart a distance greater than the averagedistance between said electrodes and being disposed in a plurality ofrows, conducting means connected between each of said electrodes and acorresponding terminal, and insulating spacer means between said walland said electrodes lying between each pair of adjacent rows of saidterminals for maintaining said electrodes spaced. from said wall andfrom said terminals and conducting means, whereby the possibility ofundesired short circuits between said electrodes, said conducting meansand said terminals is minimized.

CHARLES F. BALDWIN.

